And I'm Robert Siegel. It is the busiest day on this year's election calendar so far. Voters are going to the polls in six states across the country. In Kentucky, the ballot feature is one of the most important Senate primaries of 2014, a Tea Party-backed challenge to Senate Republican leader Mitch McConnell. There are a handful of other closely watched races with national political implications, including a few that could determine control of the Senate in November.

SIEGEL: Let's start with the marquee election taking place in Kentucky. Senator McConnell is fending off a challenge from businessman Matt Bevin. I gather things look pretty good for the senator.

GONYEA: They do and Senator McConnell is seeking a sixth term. He's seen by many as the ultimate Washington insider. Of course, he's the minority leader and that is the kind of thing that gets you a Tea Party challenge, in this case, a very well-funded one. Matt Bevin is an investment banker. He got help from outside groups. He spent more than $3 million. That's a lot of cash for a challenger taking on an incumbent in a primary.

But again, he's a newcomer. He's stumbled a few times. McConnell has also spent a ton of cash. And polls show McConnell, the incumbent, with a very comfortable lead. Still, we'll be watching to see just how big the margin is for clues as to, you know, how well he may do in November.

SIEGEL: Yes, because Senator McConnell isn't in the clear. If he wins the primary, Democrats are very hopeful still about the chances of their likely nominee in Kentucky, Secretary of State Alison Lundergan Grimes. How do things look for her in November?

GONYEA: Well, for Democrats, she is a very appealing candidate and she's someone who has already won statewide office in Kentucky, her current job, secretary of state. She is a real contrast to Senator McConnell. First, at 35 years of age, she's less than half his age. She hopes to appeal to women and to independent voters. She also knows that McConnell is not very popular. His approval ratings are in the 30s in Kentucky.

If you look at polls showing the two of them in head to head competition, McConnell and Grimes are essentially even. Look for lots of money to pour into this race. Look for it to be as tough as any in the country.

SIEGEL: Let's turn to another state with a Senate race. There is a crowded Republican primary in Georgia. What's at stake there?

GONYEA: Well, once the Tea Party saw this as a prime target. It's the race to replace outgoing, retiring Republican Senator Saxby Chambliss. The Tea Party thought they could get a conservative, one to their liking in the Senate from Georgia, but it doesn't seem to be the way it's playing out. It's a crowded field and the frontrunners are establishment types. David Perdue, he's a businessman and a cousin of the former governor, Sonny Perdue.

There's Congressman Jack Kingston and former Secretary of State Karen Handel. She's been endorsed by Rick Santorum and Sarah Palin. The sense is that two of those three will meet in a runoff in July. Nobody's expected to clear the 50 percent threshold. Down in the pack, the Tea Party favorites, Congressman Phil Gingrey and Paul Brown, they just never really got much traction.

SIEGEL: And thinking about Georgia come November, is that comfortably Republican state in recent years equally comfortable this time out for the GOP?

GONYEA: Well, it's a lot more interesting than a lot of people would've thought a couple of years back and that is because the Democrat who will emerge from the primary is Michelle Nunn. Nunn is a golden name in Georgia. She is the daughter of longtime Georgia U.S. Senator Sam Nunn, currently she runs the nonprofit Points of Light Foundation and she could make things very competitive in this red state.

But again, it doesn't help that her likely opponent in November will be a traditional conservative and not a Tea Party candidate.

GONYEA: Wehby is a pediatric neurosurgeon. She's had some really well done biographical ads, but ultimately she has been portrayed as the kind of Republican who could do wall in a blue state like Oregon in November. But she's also been criticized for not being conservative enough. A lot of opposition research has surfaced, too, Robert, including stories about a former boyfriend of hers who, years ago, accused her of stalking him.

There were no charges, but it's become an item in the campaign. It's not clear how it plays. It could hurt her. There could be a backlash and it could help her. Her opponent is a guy who has a really compelling personal story of his own, State Representative Jason Conger. He was homeless as a young man, turned his life around, made it to Harvard Law School. He is a conservative. The winner there will face incumbent Democrat Jeff Merkley.